The storage of hydrogen is a necessary prerequisite for the introduction of hydrogen-propelled vehicles. Current storage technologies, e.g., Compresses Gaseous Hydrogen (“CGH2”) or Liquid Hydrogen (“LH2”) pose a severe limitation on the driving range of such automobiles.
Solid state storage systems (e.g., classical or complex metal hydrides, e.g., FeTi2, NaAlH4 and/or the like) might be a viable alternative but will face severe heat management challenges for fundamental thermodynamic reasons. In terms of storage capacity, those compounds usually reveal a lower performance than adequate chemical hydrides (e.g., methanol, borazane, and/or the like).
The use of chemical hydrides requires a hydrogen-release and a subsequent recycling strategy of waste products. Hydrogen can be liberated from borazane (i.e., BH3NH3) by thermal decomposition, which produces a solid hydrogen-nitrogen residue hereinafter called BNH-waste.
Applicability of borazane as fuel for hydrogen-propelled vehicles is dependent on the availability of borazane in industrial scale quantities. To date, the most common synthesis routes of borazane start either directly from ammonia and diborane or from complex borohydrides, such as NaBH4, and ammonium salts. Generation of borohydride and ammonia related products are energy costly procedures. Because the residue of the dehydrogenated borazane contains the valuable materials boron and nitrogen, it would be advantageous to recycle (re-hydrogenate) the BNH-waste back to borazane. Unfortunately, a system for the re-hydrogenation of BNH-waste does not currently exist.
Accordingly, there exists a need for simple and efficient processes for the re-hydrogenation of BNH-containing waste products.